McIDAS images of MTSAT-2 10.8 Âµm IR channel data (above; click image to play animation) showed Super Typhoon Usagi in the West Pacific Ocean as it continued to move northwestward across the Philippine Sea. Note the slight amount of “trochoidal wobble” seen in the path of the eye. The coldest IR brightness temperature seen on the MTSAT-2 IR images was -92Âº C at 12:32 UTC. At the time of these images, advisories issued by the Joint Typhoon Warning Center listed the maximum sustained winds at 140 knots, with gusts to 170 knots; at its peak intensity, Usagi had an estimated lowest pressure of 882 hPa, making it the most intense tropical cyclone so far in 2013.

TMI and SSM/I 85 GHz microwave brightness temperature images

From the CIMSS Tropical Cyclones site, a comparison of 85 GHz microwave images from the TRIMM Microwave Imager (TMI) at 10:35 UTC and the DMSP SSM/I at 19:13 UTC (above) displayed a very small ring of high brightness temperatures surrounding the “pinhole eye”.

MIMIC-TC morphed microwave images (below; click image to play animation) showed a well-defined closed eyewall during much of the early part of the day on 19 September.

MIMIC-TC morphed microwave imagery (click image to play animation)

MTSAT-2 IR image with AASCAT scatterometer surface winds

Scatterometer surface winds from the ASCAT instrument at 13:17 UTCÂ (above) and the OSCAT instrument at 15:10 UTCÂ (below) showed the large areal coverage of strong winds around the center of Usagi.

AWIPS images of Suomi NPP VIIRS 11.45 Âµm IR channel and 0.7 Âµm DayNight Band data showed Hurricane Manuel centered just off the west coast of Mexico at 07:54 UTC or 12:54 AM local time (above) and at 09:37 UTC or 2:27 AM local time (below) on 19 September 2013. Manuel had just reached hurricane intensity several hours earlier. In the 07:54 UTC images above, hints of an eye feature were present on both the IR and the Day/Night Band. In the 09:37 UTC images below, evidence of offshore convective bursts could be seen (many of which exhibited cloud-top IR brightness temperatures of -80Âº C and colder, violet color enhancement).

Manuel rapidly lost organization and intensity upon moving inland over the rugged terrain of the Sierra Madre Occidental, becoming a remnant area of low pressure over northern Mexico at the end of the day on 19 September.